rgw: warning, output may be truncated before the last format character

The following warning appears during make:

```
rgw_rados.cc: In function ‘void usage_log_hash(CephContext*, const string&, std::__cxx11::string&, uint32_t)’:
rgw_rados.cc:4579:13: warning: ‘__builtin___snprintf_chk’ output may be truncated before the last format character [-Wformat-truncation=]
static void usage_log_hash(CephContext *cct, const string& name, string& hash, uint32_t index)
                 ^~~~~~~~~~~~~~
/usr/include/bits/stdio2.h:65:44: note: ‘__builtin___snprintf_chk’ output between 8 and 17 bytes into a destination of size 16
        __bos (__s), __fmt, __va_arg_pack ());
```

Signed-off-by: Jos Collin <jcollin@redhat.com>

diff --git a/src/rgw/rgw_rados.cc b/src/rgw/rgw_rados.cc
index b0b917eeadb3a8e988c5c44178e5b6f1a4705e66..be155b648e6fdbff0051932d0aa9c30fcce43593 100644 (file)
--- a/src/rgw/rgw_rados.cc
+++ b/src/rgw/rgw_rados.cc
@@ -4585,7 +4585,7 @@ static void usage_log_hash(CephContext *cct, const string& name, string& hash, u
     val %= max_user_shards;
     val += ceph_str_hash_linux(name.c_str(), name.size());
   }
-  char buf[16];
+  char buf[17];
   int max_shards = max(cct->_conf->rgw_usage_max_shards, 1);
   snprintf(buf, sizeof(buf), RGW_USAGE_OBJ_PREFIX "%u", (unsigned)(val % max_shards));
   hash = buf;